History: Summary

SUMMARY

    By the late 19th century, despite the fact that the phenomenon of current flow had not been fully explained, most known electric phenomena were successfully described by physical formulae.
    It was already possible to measure quite accurately the charge of an insulated object, the intensity of current flowing in a wire connected to a battery, or to calculate the forces acting on a known charge placed at a known distance from another charge (Coulomb's law). It was possible to reckon the magnetic field in the vicinity of a conductor with current and the force acting on the conductor through which current flows and which is placed in the magnetic field. They learnt how to reckon current induced in a wire coil placed in a variable magnetic field. They also knew how to calculate the charge which could accumulate on an insulated conductor connected to a battery of a potential that was higher than the potential of the conductor.
    Actually this knowledge had been acquired by scientists since mid 19th century. It enabled the development of many branches of technology. However, at that time a single model of the structure of electricity did not exist. Only purely empirical methods enabled scientists to gather so much information on electricity.
    Certainly there were attempts at the creation of those models. A decisive majority of scientists considered the flow of current to consist in a flow of some substance in the conductor. However, researchers differed on whether there was one, or two different "liquids". The first of those concepts assumed that there was a substance, a definite amount of which renders a body neutral, surplus makes it positive and shortage - negative. The other concept assumed the existence of two different "liquids" - a positive and a negative one. Both models explained the known electric phenomena equally well.
    Another big unknown was the structure of electricity. Some scientists shared the view that it was infinitely divisible (the liquid model) whereas others considered it to be in granular, molecular form.
    Cathode rays phenomenon was equally strange and provoked as much controversy. Scientists managed to examine and determine many of their properties like: deflection in a magnetic field, phosphorescence of glass of vacuum tube where the beam falls, the phenomenon of their perpendicular emission in the relation to the cathode, occurrence of certain photochemical reactions under the influence of the rays. It was shown that those rays transmitted energy and the direction of their divergence did not need to follow the direction of the current field in the vacuum tube. Also diffusion of rays through thin metal foils was observed. During researches of this phenomenon two theories emerged explaining their properties: one supported corpuscular and the other undulatory nature of rays. Behaviour of the rays in a magnetic field would be explained by the assumption that they constituted of molecules of negative charge. However such charge failed to be discovered. Schuster only managed to estimate that if rays actually consisted of negative molecules, their charge to mass ratio could not be less than 5*10⁶ coulombs per kilogram nor more than 10¹⁰ coulombs per kilogram.
    Scientists boasted numerous achievements in the field of the research of matter. Since the early 19th century occurrence of numerous chemical phenomena had been explained by references to the atomic theory. They managed to show that the whole variety of substances existing in nature actually consists of a small number of elements. Considering their properties, those elements can be arranged into a table - the Mendelejev's periodic table. Moreover, scientists managed to figure out many laws and relationships governing the microcosm. They formulated basic laws of thermodynamics and laws describing the ideal gas. They learnt how to determine the mean distance covered by gas molecules between collisions. Also behaviour of actual gases was profoundly researched.
    By the end of the century new elements were discovered, the existence of which was predicted by the Mendelejev's periodic table. All elements of the puzzle started to fall into place. The world was made of elements, of which an uncountable number of substances consisted of and which were the smallest components of the matter. It seemed to scientists in 1894 that the final solution of few remaining secrets of nature was the matter of a few coming years.
    However, that was not the case. Scientists only made their first step on the way to explain mysteries of the microcosm. They discovered much but even more remained to be discovered.